Heat-sealable polyolefins and articles made therefrom

Abstract

Polyolefins, preferably polyethylene, having a density of about 0.86 to about 0.93 g/mL, and having methyl branches and at least branches of two other different lengths of six carbon atoms or less, form heat seals at exceptionally low temperatures, thereby allowing good seals to be formed rapidly. This is advantageous when heat sealing these polyolefins, for example in the form of single or multilayer films.

What is claimed is:  
     
       1. A process for lowering the heat sealing temperature of a polyolefin-based thermoplastic, comprising the step of replacing at least a portion of the polyolefin in the thermoplastic with a branched polyolefin having a density of about 0.86 to about 0.93 g/mL, and having methyl branches and at least branches of two other different lengths of six carbon atoms or less, provided that said methyl branches are at least 10 mole percent of total branching in said branched polyolefin. 
     
     
       2. The process as recited in  claim 1 , wherein the branched olefin is obtainable by polymerizing an olefin in the presence of a catalyst component comprising a late transition metal catalyst. 
     
     
       3. The process as recited in  claim 2 , wherein the late transition metal catalyst is a late transition metal complex of a diimine ligand. 
     
     
       4. The process as recited in  claim 1 , wherein the branched polyolefin has a density of about 0.86 to about 0.9 g/mL. 
     
     
       5. The process as recited in  claim 1 , wherein said branched polyolefin is a homopolyethylene. 
     
     
       6. A process for preparing an article comprising the step of heat sealing a first thermoplastic surface to a second thermoplastic surface, wherein the first thermoplastic surface and the second thermoplastic surface comprise a branched polyolefin having a density of about 0.86 to about 0.93 g/mL, having methyl branches and at least branches of two other different lengths of six carbon atoms or less, provided that said methyl branches are at least 10 mole percent of total branching in said branched polyolefin. 
     
     
       7. The process as recited in  claim 6 , wherein the branched olefin is obtainable by polymerizing an olefin in the presence of a catalyst component comprising a late transition metal catalyst. 
     
     
       8. The process as recited in  claim 6 , wherein the article is a single or multilayer film. 
     
     
       9. The process as recited in  claim 6 , wherein said branched polyolefin has a density of about 0.86 to about 0.91 g/mL. 
     
     
       10. The process as recited in  claim 6 , wherein said branched polyolefin is a homopolyethylene.